1. Field of the Invention
The invention concerns a new treatment for fabric composed entirely or in part of cellulose to impart wrinkle-resistance and durable-press properties without release of formaldehyde.
2. Description of the Prior Art
Prior finishing treatments for cotton or other cellulosic fabric to impart wrinkle-resistance and the ability to dry smoothly have employed the products from the reaction of formaldehyde and an amide as finishing agents. These reaction products are methylol amides or hydroxymethyl amides. Example of these compounds are dimethylolurea, dimethylolethyleneurea, dihydroxydimethylolethyleneurea, and alkyl dimethylolcarbamates. These agents are applied to fabric with an acidic catalyst. The fabric is then heated, causing the methylol amide to react with two or more cellulose molecules and form crosslinks. The crosslinked cellulose makes a more resilient fiber than the untreated cellulose. The fiber is then less prone to suffer permanent deformations that appear in the fabric as wrinkles. To serve as a crosslinking agent, the finishing agent must possess two or more methylolamide groups in the molecular structure.
The methylol amides have been quite effective finishing agents for producing wrinkle-resistance. They do, however, suffer from a number of disadvantages. One disadvantage is that the agent and its reaction product on the fabric tend to decompose and release formaldehyde. Formaldehyde is very irritating and even small amounts are objectionable. It is also possible that even a small amount of free formaldehyde may be a health hazard.
To avoid the presence of formaldehyde the use of products from the reaction of other aldehydes and amides has been attempted. Only with glyoxal as the aldehyde replacing formaldehyde has the approach been useful, and even the agents prepared with glyoxal have not met with great success.
The problem in using other aldehydes with amides is the poor stability of the reaction product. The reaction of the aldehyde and amide to form an adduct is reversible. With most aldehydes the tendency for the adduct to decompose is great enough that a reaction mixture of aldehyde and amide gives a solution without enough adduct to be effective in treating fabric.